Computed Tomography Features of Gastric Cancer Patients With DNA Mismatch Repair Deficiency

Abstract

Objective: To explore the computed tomography (CT) features of gastric cancer (GC) patients with DNA mismatch repair deficiency (dMMR).

Materials and methods: This study reviewed the clinical and CT features of GC patients with dMMR, confirmed by the postoperative results, between September 2017 and December 2019. The expression pattern of MMR major proteins (MLH1, MSH2, MSH6, and PMS2) in immunohistochemistry was used to confirm the MMR status in GC tissues. The correlation between pre-treatment CT features and MMR status was statistically analyzed.

Results: A total of 28 patients with GC were diagnosed as dMMR in our study, and 49 patients were MMR-proficient (pMMR). The tumor locations were significantly different between the dMMR and pMMR groups (p = 0.006). The CT tumor thickness, CT long and short diameters of the largest lymph node, and the number of lymph nodes on CT of the dMMR group were significantly different from the pMMR group.

Conclusion: The dMMR GC exhibited a lower stomach location, smaller tumor thickness and lymph node diameter, and fewer lymph nodes on CT imaging.

Keywords: computed tomography; gastric cancer; microsatellite instability; mismatch repair deficiency; prognosis.

Figure 1

Flowchart of the study design.

Figure 2

(A–H): One MSI-H&dMMR GC case. Female patient, 64 years old. The postoperative pathologic results showed moderately differentiated adenocarcinoma in gastric antrum with stage T3N0M0, with no metastatic carcinoma in lymph nodes. (A) The arterial phase CT value in the enhanced arterial phase of the thickened gastric wall (arrow) in the gastric antrum was 48 HU. (B) The portal phase CT value of the thickened gastric wall (arrow) was 67 HU. (C) There was a slightly enlarged lymph node (arrow) in No. 4d group around the stomach, with a short diameter of 5 mm and CT value of 72 HU on the portal phase. (D) The case of histological analyses by HE staining. (E–H) The patient’s immunohistochemical results showed MLH1-negative (E), MSH2-positive (F), MSH6-positive (G), PMS2-negative (H), MSI-H&dMMR.

Figure 3

(A–H) One MSS&pMMR GC case. Male, 66 years old, surgical pathology results revealed poorly differentiated adenocarcinoma in the gastroesophageal junction, staging T4aN2M0, with metastatic carcinoma in lymph nodes. (A) The arterial phase CT value of the mass (arrow) in the gastroesophageal junction was 52 HU; (B) The portal phase CT value of the mass (arrow) was 82 HU; (C) Multiple enlarged lymph nodes could be seen in the stomach’s lesser curvature. The largest one had a short diameter of 15 mm (arrow), with the CT value of 88 HU on the portal phase. (D) The case of histological analyses by HE staining. (E–H) The immunohistochemical results showed MLH1-positive (E), MSH2-positive (F), MSH6-positive (G), PMS2-positive (H), MSS, pMMR.